In today's environment increased emphasis is being placed upon cleaning up and preventing pollution. A common source of pollution is oil mixed with water, due either to accidental spills, leakage, or industrial production. A common means of separating oil and water, or any other two immiscible components of different densities mixed in a fluid, is by coalescence. Coalescence is best achieved when a mixture of different density components is exposed to a material having wetting characteristics that favors either the higher density or the lower density component. A typical coalescing system uses an oleophlic material so that a lighter component, usually oil of one form or another, is attracted to the oleophlic material given the entrained oil component an opportunity to form into larger droplet sizes that will rise to the surface of the mixture.
A structure which has functioned very successfully in coalescing systems is a coalescing plate having bi-directional corrugations that run orthogonally, that is, corrugations that run both laterally and longitudinally along the single plane of the coalescing plate as illustrated and described in U.S. Pat. No. 4,897,206. The bi-directional corrugations form crests and valleys, and the crests and valleys are provided with bleed holes for passage of the immiscible components.
The bi-directionally coalescing plates of U.S. Pat. No. 4,897,206 are stacked in spaced apart arrangement and parallel to each other and arranged for a fluid mixture to flow between the plates. As the mixture flows between the plates the lighter component coalesces into droplets that grow in size until they overcome the tension that normally holds them in suspension in the mixture. The increased size droplets rise to the top of the mixture and are skimmed off, while the higher density component of the mixture, water, is drained from a lower level within the vessel. For the bi-directionally corrugated coalescing plates to function effectively they must be held in a spaced apart relationship, and U.S. Pat. No. 4,987,206 includes integral means for supporting the plates in this arrangement. However, the plates must be assembled in a package within a vessel or pit and arranged so that the mixture flows between the spaced apart plates and not above or below the plates or through spaces between the plates and the vessel walls. In the past the plates have been assembled into a package held together by either steel rods or wire. These two methods have disadvantages. In the wire method stainless steel wires with copper end clips have been used. The disadvantages of this system are that the clips come off and the wire does not have sufficient water corrosion resistance to last. Often the wires corrode completely into two pieces, whereupon the packages disintegrate into their component plates.
If stainless steel rods are used it is necessary to use cut and drill pieces of fiberglass channels at the top of the packs and to use specially formed stainless steel "feet" at the bottom of the pack. Stainless rods and nuts are used to fasten the plates together. The disadvantage of this system is that a great deal of labor is involved in cutting and drilling the channels and because the channels must be parallel to the direction of fluid flow, they cannot constitute a flow block and the plates must extend above the surface of the oil or the lighter component of the mixture. The stainless steel parts of this system are subject to attack by chlorides in the water.
The present disclosure relates to an improved system of packing bi-directional corrugated coalescing plates into a package that is easily inserted into and removed from a vessel and that is formed of components that are not subject to deterioration by water and/or oil. Further, the system of this disclosure provides improved means of ensuring that the flow of the fluid mixture is substantially completely through the spaces between the coalescing plates so as to improve the separation of lighter from heavier components of the mixture.